1. Field of the Invention
The present invention relates generally to VLSI chips and, more particularly, to an optical method for communicating between a transmitter VLSI chip and a receiver VLSI chip such that the noise characteristic of communication between chips is limited.
2. Description of the Related Art
The bandwidth for the transmission of data between very large scale integrated (VLSI) chips in modern computers is limited by noise. Much of this noise is produced by rapid changes of electrical current, and is called switching noise or xcex94-I noise. Because data transmission between devices requires substantial electrical power, interdevice data transmission produces a substantial fraction of observed switching noise, and thereby contributes to the bandwidth limitation on data rate.
Therefore it is an object of the present invention to provide an apparatus and method for transmitting data between VLSI chips which reduces the noise characteristic with communications between VLSI chips.
It is yet a further object of the present invention to provide an apparatus and method for transmitting data between VLSI chips which increases data transfer rates over methods currently employed in the arts.
It is the purpose of this invention to power both the transmission and the reception of data in a manner that contributes minimally to switching noise. The power for both transmission and reception of data is supplied from an external laser in a way that greatly reduces current transients within a VLSI device. Consequently, data rates are potentially faster with this means than with electrical means.
Accordingly, a transmitter for transmitting data in the form of an optical signal and a receiver for receiving data in the form of an optical signal are provided. The transmitter comprises: a transmitter chip module having a material capable of radiating light of a first wavelength when both a zero voltage potential exists across the material and when illuminated by light of a second wavelength; a light source optically coupled to the transmitter chip module for illuminating the material with light of the second wavelength; and voltage control means for controlling the voltage potential across the first material. The receiver comprises: a receiver chip module having a material capable of producing a signal in the form of a produced voltage potential or produced current flow when illuminated by light of both the first wavelength and light of a second wavelength; a light source optically coupled to the receiver chip module for illuminating the material with light of the second wavelength; and signal detecting means for detecting the presence of the produced signal.
In a first preferred implementation of the transmitter and receiver of the present invention, a first apparatus for transmitting data between first and second VLSI chips is provided. The first apparatus comprises: a transmitter disposed on the first VLSI chip, the transmitter having a first material capable of radiating light of a first wavelength when both a zero voltage potential exists across the first material and when illuminated by light of a second wavelength, the transmitter further having voltage control means for controlling the voltage potential across the first material; a receiver disposed on the second VLSI chip, the receiver having a second material capable of producing a signal in the form of a produced voltage potential or produced current flow when illuminated by light of both the first wavelength and a third wavelength, the receiver further having signal detecting means for detecting the presence of the produced signal; at least one light source optically coupled to the transmitter and receiver for illuminating the first material with light of the second wavelength and for illuminating the second material with light of the third wavelength; and light transmission means for transmitting the light of the first wavelength from the transmitter to the receiver.
In a second preferred implementation of the transmitter and receiver of the present invention, a second apparatus for transmitting data between first and second VLSI chips is provided. The second apparatus comprises: a plurality of transmitters disposed on the first VLSI chip, each transmitter having a first material capable of radiating light of a first wavelength when both a zero voltage potential exists across the first material and when illuminated by light of a second wavelength; a plurality of receivers disposed on the second VLSI chip, each receiver corresponding to a transmitter on the first VLSI chip, each receiver having a second material capable of producing a signal in the form of a produced voltage potential or produced current flow when illuminated by light of both the first wavelength and a third wavelength; voltage control means for individually controlling the voltage potential across the first material of each transmitter; signal detecting means for individually detecting the presence of the produced signal from each receiver; at least one light source optically coupled to each of the transmitters and receivers for illuminating the first material of each of the transmitters with light of the second wavelength and for illuminating the second material of each of the receivers with light of the third wavelength; and light transmission means for transmitting the light of the first wavelength from each of the transmitters to a corresponding receiver.
In a preferred versions of the first and second apparatus of the present invention, first and second light sources are provided. The first light source providing light of the second wavelength, the second light source providing the light of the third wavelength.